Added success notification on launch wizard completion

no issue

- provide an indication of success and a "next step" option

ghost/admin/app/components/gh-launch-wizard/finalise.js

@@ -1,14 +1,20 @@
 import Component from '@glimmer/component';
+import {htmlSafe} from '@ember/string';
 import {inject as service} from '@ember/service';
 import {task} from 'ember-concurrency-decorators';
 
 export default class GhLaunchWizardFinaliseComponent extends Component {
     @service feature;
+    @service notifications;
     @service router;
 
     @task
     *finaliseTask() {
         yield this.feature.set('launchComplete', true);
         this.router.transitionTo('dashboard');
+        this.notifications.showNotification(
+            'Launch complete!',
+            {type: 'success', actions: htmlSafe('<a href="#/posts">Start creating content</a>')}
+        );
     }
 }